module mux3_1(
        input [1:0]s,
        input [7:0]a,
        input [7:0]b,
        input [7:0]c,
        output reg [7:0]y
    );
    always @(*) begin
       case(s)
          2'b00:y=a;
          2'b01:y=b;
          2'b10:y=c;
          default:y=a;
       endcase   
    end
endmodule